A conventional charging device for charging a battery of a portable electronic device includes a desk top charger (DTC), a portable charger that travelers use, a vehicle charger in which a cigar jack power of a car is used as a charging power and so on. Among them, the portable charger rectifies domestic AC 110V/220V into DC power and steps down it using a switching mode power supply to DC power with a predetermined voltage level suitable for charging, to charge the charging battery of the portable electronic device.
FIG. 1 illustrates the configuration of a conventional portable charger. In FIG. 1, a reference numeral 1 denotes a charger body including a switching mode power supply and a charging circuit, a reference numeral 2 represents a power plug connected to a domestic electric outlet 6, a reference numeral 3 indicates an interface jack connected to an interface connector of a cellular phone 5, and a reference numeral 4 denotes a cable for connecting the charger body 1 to the interface jack 3.
In this configuration, when the interface jack 3 is coupled to the interface connector of the cellular phone 5 and the power plug 2 is connected to the electric outlet 6, home AC power applied to the charger body 1 through the power plug 2 is transformed into DC power having a predetermined voltage level to charge the charging battery of the cellular phone 5.
However, the aforementioned conventional portable charger can be use in only a place having the electric outlet 6 that supplies home AC power. Thus, the portable charger cannot perform its charging operation in a place having no electric outlet or in the event of suspension of electric supply. To solve this problem, the charger for a car has been proposed.
When a user is distant from the car, however, he or she cannot use the charger. Furthermore, in the case where the user needs both the portable charger and the vehicle charger, he or she suffers from an inconvenience of having to carry the two chargers and spends unnecessary money on purchasing them. Moreover, the conventional chargers can be used only for a specific type of portable equipment and they cannot be used for other types of portable equipment.